Memory cards essentially comprise a card body which is generally made of a plastic material together with a memory module. In cards having an electronic memory, the memory module is an electronic module essentially comprising a semiconductor chip having an integrated circuit formed thereon together with a piece of printed circuit having the chip fixed thereto and serving to define external contact tabs. The electronic module is fixed in the body of the card so that the electrical contact tabs are level with one of the main faces of the card body.
The card body is in the form of a rectangular parallelipiped having a thickness which must be less than 1 mm. The edges of the card body serve as references for positioning the card in a card reader so that the contact tabs of the card come into electrical contact with a connector in the card reader.
Two main techniques are used for making the card body and for implanting the electronic module therein. In the first technique, the card body is made by hot rolling a plurality of sheets of plastic material such as PVC. The electronic module is put into place in the stack of sheets of plastic material prior to rolling. After the rolling operation, the electronic module is solidly retained in the card body. This method has the advantage of making the card body and implanting the electronic module therein in a single step. However, it is a difficult method and requires the periphery of the card body to be re-machined.
The second technique consists in making the card body in a first step, in machining a cavity in the card body to receive the electronic module, and in gluing the electronic module in the cavity. The machining of such a card body is always a difficult operation and is therefore expensive because very accurate tolerances must be maintained, in particular to ensure that the electronic module is properly positioned relative to the edges of the card and relative to the main face of the card body with which the electrical contact tabs are to be level.
It should also be added that the card body must additionally satisfy other specifications concerning the quality of its surface state and concerning well-defined bending properties both longitudinally and trnasversely relative to the card body. In addition, the card body must not encourge the storage of electrostatic charge.
An aim of the present invention is to provide a method of making cards, in particular cards having an electronic memory, and in particular for making the card body in such a manner as to reduce the cost of making a card body while also simplifying the operation of fixing the electronic module in the card body and yet still satisfying the above-mentioned specifications.